The understanding of the molecular basis for membrane traffic has made rapid progress in recent years. By convergence of work from yeast genetics, molecular neurobiology, and classical cell biology, major discoveries that have been made include the identification of proteins involved in membrane traffic and of their point of action; the demonstration of the roles of key proteins in fusion such as rab proteins, NSF, and synaptotagmins; and initial insight into fusion mechanisms. In addition, it is now becoming clear that several important diseases, such as Alzheimer's disease and Parkinson's disease, may involve mechanisms related to membrane traffic (e.g. APP processing, synuclein). The major problem in membrane traffic now is to gain a mechanistic understanding of processes such as docking, fusion, and budding, and to determine what role aberrations of these processes have in diseases. In this regard, understanding the physicochemical basis for membrane trafficking reactions such as fusion is probably the most important future challenge. This understanding will require a multidisciplinary approach uniting different methodologies. The purpose of th0e proposed meeting is to bring together key investigators studying molecular mechanisms in membrane traffic in diverse systems, including selected pathologies. We hope that by bringing people with different expertise and sometimes opposing viewpoints together, their discussions will help to further focus the field into a productive area. This will allow formulation of new concepts and approaches for studying mechanisms of membrane traffic, and will give students and postdoctoral fellows a chance to gain access to different opinions in this field.